Stocks ended a volatile session slightly lower Monday as investors welcomed a slight increase in U.S. consumer spending but remained cautious ahead of key economic reports due later this week. Stocks struggled for direction throughout the session as investors considered a pledge from Group of Twenty (G20) leaders to cut public deficits over the next few years. Investors also were still nervous and the Europe debt crisis and the possibility that the U.S. economy falls into a second recession. In U.S. economic news, personal income rose a smaller-than-expected 0.4 percent in May, while personal spending rose a bigger-than-expected 0.2 percent. The U.S. dollar rose against the euro and was flat versus the yen. Light sweet crude oil for August delivery fell 90 cents to $77.96 a barrel on the New York Mercantile Exchange. Gold fell $16.60 to $1,239.20 an ounce. The Dow Jones industrial average was little changed, falling 5.29 to 10,138.52. The broader Standard & Poor's 500 index fell 2.19, or 0.2 percent, to 1,074.57. The technology-heavy Nasdaq composite index fell 2.83, or 0.1 percent, to 2,220.65.